1. Technical Field
The present disclosure relates to an enclosed derrick structure of an arctic ship, and more particularly, to an enclosed derrick structure of an arctic ship, which provides an installation space for an exhaust unit at an upper portion of an enclosed derrick.
2. Description of the Related Art
Due to the rapid international industrialization and industrial development, the use of the earth's resources, such as oil, is gradually increasing. Accordingly, stable production and supply of oil is emerging as a very important worldwide issue.
For this reason, much attention has recently been paid to development of small marginal fields or deep-sea oil fields, which have been ignored because of their low economic feasibility. Therefore, with the development of offshore drilling techniques, drill ships equipped with drilling equipment suitable for development of such oil fields have been developed.
In conventional offshore drilling, rig ships or fixed type platforms have been mainly used, which can be moved only by tugboats and are anchored at a position on the sea using a mooring gear to conduct an oil drilling operation. In recent years, however, so-called drill ships have been developed and used for offshore drilling. The drill ships are provided with advanced drilling equipment and have structures similar to typical ships such that they can make a voyage using their own power. Since drill ships have to frequently move in order for development of small marginal fields, they are constructed to make a voyage using their own power, without assistance of tugboats.
Meanwhile, a moonpool is formed at the center of a rig ship, a fixed type platform or a drill ship, such that a riser or a drill pipe is vertically movable through the moonpool. In addition, a derrick in which a variety of drilling equipment are integrated is installed on a deck.